Author: Daniel Clausen
Date: 07:21:41 09/04/03
Go up one level in this thread
On September 03, 2003 at 14:53:23, Robert Hyatt wrote: >I finally found time to run a few tests. > >First, the set-up: I took all my bitmap stuff, added it up, and put it in >a structure that was then set up as an array. IE tdata[128] was an array >of these structures, each element being just enough bytes to hold all of what >I call a "position" including bitmap boards, hash signature, 50 move counter, >etc...) > >At the top of MakeMove() I added tdata[ply+1]=tdata[ply]; to do the copy >stuff. That's all. > >Some results: > >fine 70 searched to 39 plies deep: > >copy/make : 15.5 seconds, make/unmake 14.0 seconds (11% overhead) > >kopec 22 searched to 12 plies deep: > >copy/make : 32.4 seconds, make/unmake 28.3 seconds. (14.5% overhead) > >mate position searched 9 plies deep (mate in 10) > >copy/make : 8.9 seconds, make/unmake 7.5 seconds. (18.7% overhead) That together with the KISS principle strengthens me in the view that I will stay with the copy/make strategy until my engine is at the top, which will never happen anyway. Even if the numbers in other setups can be slightly higher, it translates to what, 10-20 ELO? Well, I can imagine tons of other places to work on my engine and gain more than that. Yeah, I can see why the author of a top-program would do that, since 20 ELOs can be crucial to become number one or not in this famous SSDF, and that's probably rather important for sales. But for a mortal as me, I couldn't care less. _Maybe_ I'll do it when I'm sure that the board structure etc doesn't change too much in the distant future... >That's not all the story. however. The copy/make approach requires an >extra register everywhere since the data structures have to be accessed >through a pointer (or via an array subscript, same thing). Well, I guess there's no difference in my engine, because I don't have any global variables anyway. ( I assume you don't need a pointer (and therefore an additional register) because your board structure is global?) Sargon
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